New / Replacement pistons & rings

I got lucky last year and managed to find a set of NOS piston rings for my KZ305, It seems like they didn't 'take' well because I get a smokey exhaust when I have any strain on the engine like going up hill. I got the valve guide seals replace - ouch cost me 400 bucks, but that has not solved the problem.

So The next move would be to go to a 0.5 over bore but I cant get the pistons or rings (well extensive internet searches come up with nothing) So what is the process to get custom pistons & rings made. I know this will cost plenty but if I got it done the engine would be like new again so worth it.
Eventually I'd love to pass this bike on to my son so long term it will be worthwhile.
The part numbers are 13025-1007 for the 0.5 rings & 13029-1019 for the pistons.

Some other issues left side carb is always wet with fuel. I've checked the float levels, the floats move freely and the float valves look fine. I could try bending the tank to really drop the float level but if I go too far it will effect performance right?

I checked & re-set all the valve clearances to spec, it's running well but the valves are noisier with a constant tapping sound - anything to worry about there?

I also found a couple of small holes in a diaphragm, I tried the gorilla glue fix, it hasn't worked 100% but it is better - as in slides down slower than before. How does this effect performance?

Any answers greatly appreciated as always!

P.S. after a couple of vintage Kawis coming up on TradeMe recently there are none right now. Getting harder to get...

Perhaps the oil ring was damaged during installation or incorrectly installed. Which would likely not affect compression reading, but would allow oil into the combustion chamber to create smoke from the exhaust.

Would perform a compression test and a leak-down test.

Good Fortune!

If your carb is flooding the cylinder, the rings are being washed out. Fix that first. The problem may go away. If not, you can try re honing the cylinders with a course hone. Too many times guys buy a deglazing hone and think ii's good. It needs a rough cross hatch so the rings will seat.
Steve

swest wrote: If your carb is flooding the cylinder...Fix that first. The problem may go away....

Yes. If the crankcase oil has been contaminated and diluted with gasoline, it could cause the smoking exhaust. Because the diluted oil gets past the oil rings and into the combustion chamber.

Perform the sniff-test on the crankcase oil, and examine its physical quality.

If diluted with gasoline, do fix that first.
It's often caused by a leaking float valve (for whatever reason).
And of course change both oil and filter before again starting the engine.

Good Fortune!

There may indeed still be some trouble in ringville, but diagnosing a problem is usually easier and more accurate when all systems are as close to optimal as possible.
A torn diaphragm in a carb can lead to wonky idle, poor throttle response and even excessive engine noise as the two carbs will be out of synchronization . More often than not, a replacement diaphragm is the only solution.
Fuel height, not float height, is very important. The factory service manual and several dozen posts on this board carefully describe the correct procedure. If you don't have a copy, get one. In the mean time, try the searc box here for "clear tube."
Re-synchronize the carburetors and move on to the next problem. Actually, carefully following the major tuneup procedure in the factory service manual would be a good way to get all those systems up to par and may identify other problems needing attention.
Even if the smoking remains, these things will need to be done for the engine to operate as it should.

when it comes time to install new rings surface finish is very important".According to research by Perfect Circle, a plateaued bore surface will stabilize after about two hours of running. In other words, the rings will seat very quickly and experience almost no further wear. A more conventional surface finish, by comparison, may take anywhere from three to 12 hours to seat in depending on the grade of stones used. A bore finish honed with #280 grit stones will seat faster than one finished with #220 stones".some times you are better off letting a shop hone your cyclinder.

kawi810 wrote: .... A bore finish honed with #280 grit stones will seat faster than one finished with #220 stones".some times you are better off letting a shop hone your cyclinder.

Did you mean that the #280, if being a finer grit stone, will seat faster or the other way around?

yes ,check with machine shops and see what # grit they are finnish honing there cylinders . my shop uses # 280 grit.

I do indeed have the manual, I have the book & the pdf version on all my computers, my tablet & my phone - don't leave home without it! For a 'full tune up' there is the 'Engine Adjustment' section which covers a lot of that stuff.
I'll try to get another diaphragm / vacuum piston part - they are spendy! Has anyone had any luck with the aftermarket diaphragm only replacement (& from where?) Woah hang on! I just found one on e-bay for $45 + 9 bucks shipping to NZ! My lucky day!

It's mostly my right cylinder that is smokey and I think it always has been even before the new rings were fitted - hence doing them in the first place. Usually it is the left carb the low side on the side stand that is damp with fuel. Last time in the carbs I swapped the float & float valve to see if it made any difference. It did - they are both damp now!

So the float needles are easy enough to get. Are the aftermarket ones ok? I've inspected mine several times and they look fine - no groove around the viton but I almost need a magnifying glass to see properly they are so small.
Ive done the clear hose test and it looked ok but I can try it again. Bend the tang to suit...

Also my petcock is stuffed, the rubber part with the hole is mangled and doesn't work. It makes taking the tank off a real PITA! I guess I should sort that out too.

Thanks for all the great advice team. It certainly gives me a path to follow.

Don't bend the tang too much on an angle. That will cock the needle to one side and cause a leak. If needed bend the float balls so everything is even.
Steve

The O-rings on my float bowls don't look like they will seal very well, they are squashed flat, could that be contributing to the wetness on the outside of the bowls? Or should the fuel be sitting below that level any way?

Do the clear tube test.
Steve